The present invention relates in general to an image forming apparatus in which degradation of the visibility of printing is reduced or eliminated when printing on paper. More particularly, the invention relates to an image forming apparatus that is useful for monochromatic printing of a color image or a gray scale image.
Japanese Patent Application Laid-Open No. Heisei 5 (1993)-250113 discloses a technique for obtaining a conspicuous monochrome image during monochrome printing of an image, in which color image data and code data are mixedly present, by outlining in an image around a portion where image data and code data overlap.
However, when the area around the portion in an image where the image data and the code data overlap is outlined, a gap relative to an original image becomes large so as to produce an unnatural image.
It is therefore an object of the present invention to obtain a natural image with good visibility during printing.
According to a first aspect of the present invention, an image forming apparatus comprises: a data buffer storing input print data; a judgment portion for making a judgment as to whether a defined statement of a predetermined character is included in data stored in the data buffer; and a line screen value converting portion for converting a line screen definition for performing halftone printing of a predetermined character when a defined statement of the predetermined character is contained in data stored in the data buffer.
In the preferred construction, the line screen value converting portion may comprise: a first information input terminal for receiving an input of a value of line screen to be converted; a second information input terminal for receiving an input designating a font size to be a conversion object; a font size comparing portion, that is active when there is a description of the font size in the data in the data buffer, for comparing the font size with a font size received via the second information input terminal; a line screen conversion character string storage portion for storing an additional character string for performing line screen conversion; and a selector for switching an output between input print data and the line screen conversion character string on the basis of a result of judgment in the character string judgment portion and a result of comparison in the font size comparing portion.
The line screen value converting portion may comprise: a background color information extracting portion for extracting information of a background color from the print data; and a line screen value determining portion for determining a line screen value for conversion while taking the extracted background color into account.
According to a second aspect of the present invention an image forming apparatus comprises: a data buffer storing input print data; a character string judgment portion for making a judgment as to whether a defined statement of a predetermined character is present in data stored in the data buffer; and a color information converting portion for converting a color definition of the character to be printed.
In the preferred construction, the color information converting portion may comprise: a color judgment portion for extracting color information from the data in the data buffer and for making a judgment as to whether degradation of visibility can be caused upon gray scale conversion; a color conversion character string storing portion for storing a character string to perform color conversion; and a selector for switching an output between the input print data and the character string with a converted color definition on the basis of a result of judgment in the character string judgment portion and a result of comparison in the font size comparing portion.
The color information converting portion may comprise: a background color information extracting portion for extracting information of the background color from the print data; and a color information determining portion for determining color information to be converted on the basis of extracted background color information.
According to a third aspect of the present invention, an image forming apparatus comprises: a data buffer temporarily storing print data input through an input terminal; a print data converting portion, that is active when the description of a character is contained in data temporarily stored in the data buffer, for converting the print data for enhancing the visibility of the character; an output terminal for externally outputting the print data after conversion; and a process end signal output terminal for externally outputting a signal when the end of the print data is detected by a data end judgment portion.
The print data converting portion may comprise: a first information input terminal for receiving an input of a value of line screen to be converted; a second information input terminal for receiving an input designating a font size to be conversion object; a font size comparing portion that is active when there is a description of the font size in the data in the data buffer, for comparing the font size with a font size received via the second information input terminal; a line screen conversion character string storage portion for storing an additional character string for performing line screen conversion; and a selector for switching an output between input print data and the line screen conversion character string on the basis of a result of judgment in the character string judgment portion and a result of comparison in the font size comparing portion.
In such a case, the line screen value converting portion may comprise: a background color information extracting portion for extracting information of a background color from the print data; and a line screen value determining portion for determining a line screen value for conversion while taking the extracted background color into account.
In the alternative, the print data converting portion may comprise: a color judgment portion for extracting color information in the data in the data buffer and making a judgment as to whether degradation of the visibility can be caused upon gray scale conversion; a color conversion character string storing portion for storing the character string to perform color conversion; and a selector for switching an output between the input print data and the character string with a converted color definition on the basis of a result of judgment in the character string judgment portion and a result of comparison in the font size comparing portion.
The color information converting portion may comprise: a background color information extracting portion for extracting information of the background color from the print data; and a color information determining portion for determining color information to be converted on the basis of extracted background color information.
According to a fourth aspect of the present invention, an image processing system comprises: a printer driver for converting input image data into print data; and a printer apparatus for performing data output using the converted image data, the printer driver including at least the image forming apparatus set forth above.
According to a fifth aspect of the present invention, an image processing system comprises: a printer driver for converting input image data into print data; and a printer apparatus for performing data output using the converted image data, the printer apparatus including at least the image forming apparatus as set forth above.
According to a sixth aspect of the present invention, an image forming method may comprise the steps of: parsing information of input print data; converting the print data based on the parsing; and outputting data on the basis of a print data process through the conversion process.